Pontic tooth



Oct. 28, 1947. w FROM 2,429,931

' PON'IIC TOOTH 'F'iled Sept. 27, 1945 LUTHER l/V FROMM I INVENTOR ATTORN EY Patented Oct. 28, 1947 UNITED STATES PATENT OFFICE 21,429,831 PONTIC TOOTH Luther W.,From m, Seattle, Wash.

Application September 27, 1943, Serial No. 504,019

The present invention relates to the construction of a pontic tooth and in more particular to the construction of 1a pontic or other artificial tooth and the backing therefor which will allow assembly thereof by motion transversely of the longitudinal axis of the tooth.

Artificial teeth, in the prior art, have had their appearance marred by the whole of the back of a tooth being covered by the metal backing, This gives'the teeth a dark or dull appearance, and further reduces their desirability by the fact that the metal could be seen along the margins of each tooth. Any eiiort in the prior art to reduce the size and extent of the backing, has led to a tooth which was weak, in that it would easily break away from the reduced backing. In the prior art, any reduction in the size of the backing has resulted in a reduction in the contact between the backing of adjacent teeth. This has allowed food particles to become lodged between the teeth and has, also, materially reduced'the strength of the teeth when set together.

Having in mind these defects of the prior art, it is an object of the present invention to construct a tooth that has a backing over a, very small part of the back, and that along the gingival line of the tooth.

Another object of the present invention is the construction of a tooth and backing in which the backing covers a small part of the tooth and, yet, in, which "the backing extends along all of the contact surfaces.

A further object of the present invention is the construction of a tooth and backing which when assembled together will form a solid unit not easily separated.

A further object of the present invention is the construction of a tooth and backing that will provide a variable contact surface between adjacent teeth.

A further object of the present invention is the construction of a tooth and a backing therefor which are assembled by relative movement transversely of the longitudinal aXis of the tooth.

Yet another object of the invention is the provision of a solid metal base extending well into the tooth for taking up of longitudinal forces upon the tooth.

These defects of the prior art have been remedied and these objects attained by means of the present invention, wherein I form a tooth with a plurality of transverse grooves and the backing with lands that fit in these grooves, which lands are widely distributed. so as to obtain a well braced 4 Claims. (Cl. 32-10) tooth. The grooves are arranged on the proximal and lingual surfaces so as to leave the upper 'the tooth and backing fit together by relative movement transversely of their longitudinal axes. The proximal portions of the backing extend far enough along the tooth so that adjacent teeth may be joined along their proximal surfaces and the position of contact determined by the height to which thesolder joining the proximal surfaces is run. Also, particularly in the case of molars, the proximal portions of the backing may be extended to the, occlusal surface to provide for a hard bite contact.

' A tooth constructon that will conform to the above outline of construction, will remedy the above mentioned defects, and achieve the named objects, is shown in the accompanying drawings, wherein:

Figure 1 is a perspective view of an incisor tooth and backing in assembled relation and embodying my invention.

' Figure 2 is a perspective view of the tooth shown in Figure 1, but with th backing removed.

Fi ure 3 is a perspective view of the backing shown in Figure 1, but without the tooth.

Figure 4 is a section on the line 4-4 of Figure 5, showing in section the tooth and backing of Figures 1, 2, and 3.

Figure 5 is a section on the line 5-5 of Figure 4.

Figure 6 is a section on the line 6--6 of Figure 5.

Figure 7 is a section on the line 1'l of Figure 5.

Figure 8 is a perspective view of a molar tooth and backing in assembled relation, and embodying my invention.

Figures 1 to 7, inclusive, are views of an incisor tooth I and a backing 2 embodying my invention. The tooth and backing are so constructed as to fit smoothly together. A deep slot 3 is formed in the base across the back of the tooth and at or close to the lingual edge. The backing has a similar portion 4 adapted to fit in the slot. A groove 5, l, is formed in each proximal surface and the backing has a land 6, 8, that fits into each of these grooves. In the lateral parts of each tooth there is formed a socket 9, II. Into priate.

each socket there is adapted to fit a pin l0, [2 which is attached to the slot portion 4 of the backing. Each pin is anchored to the backing at its base as well as by means of a web [4, I6. Corresponding openings I3, l5 are cut in the tooth. Centrally of the tooth and in the basal part thereof is formed a socket [1 adapted to receive a pin I8 attached to the backing. This pin is also strengthened by means of a web 20 connecting it to the backing. The base of the pin is secured to an extension of the backing, but the only connection thereto could be thru the web 20. The tooth has formed therein a slot l9 for reception of the web 20 of the central pin l8.

The manipulations for taking impressions and for setting a backing in a bridge are well known to the art. The present backing when used gives an open slot 3 into which it is easy to place solder for uniting the backing with other members of the bridge. The lateral, or proximal, surfaces 6, 8, form contact surfaces with adjacent teeth to which they may be secured by soldering if appro- These surfaces, in that they extend out well away from the central portion of the tooth, also, serve to securely brace the tooth. This principle of widely dispersing the backing and its anchoring means is fundamental to a satisfactory tooth design. The present construction offers a maximum in this respect. The three pins are widely spaced and form the points of a large triangle. The proximal lands extend far up on the tooth to form extended anchors, and, yet, do not detract from the good appearance of the tooth.

The present construction, also, allows the use of a means such as the webs I 4, I6, 20 for bracing the pins l0, l2, l8. This has been a serious defect of the prior art as, therein, the pins have usually been attached to the backing by their bases only.

Figure 8 is a perspective view of a molar tooth 2| and backing 22 having embodied therein my present invention. The construction of this tooth and its backing is very similar to the tooth and backing shown in the previous figures and for this reason the parts thereof have not been shown in such detail. The principal difference between the two constructions is that the proximal portions 26, 28 of the backing have been carried to the occlusal surface. This provides a portion of the occlusal surface that may easily be made hard wearing, and allows the direct transmission of strains from the occlusal surface to the backing without going thru the removable, or tooth, portion. This construction, also, allows the use in the tooth of some of the softer plastics, as the wear is taken by the proximal portions that extend to the occlusal surface.

Having thus described my invention, I claim:

1. An artificial tooth formed with connecting grooves extending transversely of its proximal and lingual surfaces in such a manner that a mating backing will have a U-shaped form, the groove in the proximal surface being adjacent the gingival surface and away from the occlusal surface.

. 2. An artificial tooth formed with connecting grooves extending transversely of its proximal and lingual surfaces, said grooves including three sockets triangularly spaced apart, and the axes of said grooves and sockets being parallel to each other.

3. An artificial tooth formed with connecting grooves extending transversely of its proximal and lingual surfaces, said grooves extending along the proximal surfaces and across the interior lingual surface adjacent the gingival surface and. away from the occlusal surface with sockets formed in the base portion thereof, and the axes of said grooves and sockets being parallel to each other.

4. An artificial tooth formed with connecting grooves extending transversely of its proximal and lingual surfaces, said grooves extending along the proximal surfaces and across the interior lingual surface, adjacent the gingival surfaces and awayfrom the occlusal surface with sockets formed in the base portion thereof, web slots connecting the sides of said grooves and sockets, and the axes of said grooves and sockets being parallel to each other.

LUTHER W. FROMM.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

